By the outbreak of war Bentley was effectively out of work. His family firm had been selling cars but trading soon ceased. Cars still had to be serviced but with his business in ruins for as long, it seemed, as the war lasted, WO wanted to make the most of his great secret scoop. He had been one of the first to adopt aluminium pistons in the DFP in which he set ftd for his class at the Aston Clinton hill-climb. He set a ten-lap record at Brooklands for a 2 litre car at 66.8mph (107.5kph) and a year later, with L8 aluminium pistons, raised it to 81.9mph (131.9kph).
He now wanted to put this breakthrough at the disposal of the nation. It would be just the thing, he was sure, for high performance aircraft engines. He sought out Commander Wilfrid Briggs, head of the Air Engine Section, which liased between the Admiralty and the engine industry. Briggs operated from a small wooden office on top of Admiralty Arch and captured WO’s attention at once. “The only officer in the navy as clever as Briggs was the man who appointed him,” wrote WO, recounted in The Complete Bentley.
By June 13 1915, less than a year after the grand prix, Briggs had WO Bentley gazetted as a Lieutenant in the Royal Naval Volunteer Reserve (RNVR), an elite bunch of civilian volunteers who obtained quick promotion for wartime officers into the Royal Naval Air Service (RNAS). Briggs sent WO to Derby, where Rolls-Royce was making air-cooled Renault aero engines, to meet Ernest W Hives (later Lord Hives) with whom WO formed a friendship that lasted 20 years. Engineer Hives soon had Rolls-Royce’s new 200hp water-cooled Eagle engines equipped with aluminium pistons.
Henry Royce was adept at meticulous improvement rather than radical innovation. WO was determined he should get to know more of his adversary’s engineering. WO recalled that in 1915: “…a friend of mine tipped me off that one of the Mércèdes racing cars, which had swept the board at the 1914 French Grand Prix, had got stuck in England at the beginning of the war and still rested at the Mércèdes showroom in Long Acre. I thought it ought to be investigated. So I told Briggs about it and together we went along, representing the British Crown so to speak, with a ‘search warrant’. The place was in a fine old mess, but down in the basement lay a 4½ litre Grand Prix Mércèdes. We had it dug out, and soon it was being taken to pieces by Rolls-Royce at Derby.”
There was no search warrant of course and accounts of the legitimate wartime larceny differ. In one WO towed the Mércèdes to Derby behind Briggs’s Rolls-Royce. In another he recruited his old school friend Roy Fedden, later a distinguished engineer at Bristol Aircraft, and the pair raced along empty wartime roads from London to Derby, before towing the 1914 racer into the Rolls-Royce factory.
The precocious young Lieutenant also recommended that Rolls-Royce examine the contemporary double overhead camshaft Peugeot racing engine.